Analog Devices Inc./Maxim Integrated MAX6865UK23D1L+T

Overview

The MAX6865UK23D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (reset threshold = +2.23V), manual reset input (MR), and watchdog timer (timeout = 209s typ) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 10ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK23D1L+T datasheet, MAX6865UK23D1L+T pinout, MAX6865UK23D1L+T application, or MAX6865UK23D1L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), factory-trimmed 2.23V threshold, and lead-free SOT23-5 packaging compatible with automated assembly.

Technical Context

This device integrates a precision bandgap-based voltage monitor, a digital watchdog timer with edge-triggered WDI input, and a monostable reset timeout generator. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable direct switch interfacing without external components.

The watchdog logic clears on any WDI edge (rising or falling), resets only after full timeout expiration (209s typ), and remains disabled while RESET is asserted - preventing spurious timeouts during power-up or reset recovery sequences.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, RoHS-compliant, footprint-compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6864UK23D1L+T and TPS3836K33DBVR, the MAX6865UK23D1L+T uniquely delivers active-high RESET, ultra-low 170nA ICC, and certified 209s watchdog - making it the sole option meeting simultaneous requirements for low-power medical wearables with firmware supervision.

Availability

MAX6865UK23D1L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and smart wearable health trackers requiring stable component supply across long production lifecycles.

Supply support for MAX6865UK23D1L+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs high-performance analog and mixed-signal ICs for power, sensing, and timing applications in industrial, medical, and consumer markets.

The MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-constrained systems, emphasizing nanopower operation, robust reset timing, and integrated watchdog functionality for safety-critical firmware monitoring.

FAQ

What is the exact reset threshold voltage of the MAX6865UK23D1L+T?

The MAX6865UK23D1L+T has a factory-trimmed reset threshold of +2.23V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "23" corresponds to 2.23V. The device guarantees valid reset assertion down to VCC = +1.1V, supporting reliable brownout detection in low-voltage systems.

Does the MAX6865UK23D1L+T require external components for basic operation?

No, the MAX6865UK23D1L+T operates autonomously with no external components required. It integrates a 10kΩ internal pullup on MR, precision voltage reference, and monostable timeout generator. Only a 0.1µF ceramic capacitor from VCC to GND is recommended for noise suppression - a standard practice for all ICs, not a functional requirement.

How does the watchdog timer in the MAX6865UK23D1L+T respond to firmware activity?

The MAX6865UK23D1L+T watchdog timer clears on every rising or falling edge at the WDI pin and expires only if WDI remains static for ≥209s (typical). It does not count while RESET is asserted. This behavior ensures robust detection of firmware hangs - including stuck loops - without false triggers from brief I/O glitches or slow clock domains.

What is the function of Pin 1 (RESET) on the MAX6865UK23D1L+T?

Pin 1 of the MAX6865UK23D1L+T is the active-high push-pull RESET output. It drives high (to VCC) when asserting reset due to VCC drop, MR activation, or watchdog timeout, and drives low when deasserted. Unlike open-drain variants, it requires no external pullup and can source/sink up to 1.2mA - enabling direct interface with standard CMOS µP reset inputs.

Is the MAX6865UK23D1L+T compatible with lead-free reflow processes?

Yes, the MAX6865UK23D1L+T uses lead-free packaging and is rated for standard Pb-free reflow profiles (JEDEC J-STD-020). The "+T" suffix explicitly denotes lead-free compliance, and the SOT23-5 package withstands peak temperatures up to +260°C for 30 seconds - fully compatible with IPC-A-610 Class 2 and Class 3 assembly requirements.